#include <iostream>
#include <algorithm>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    long long A, B, K;
    cin>>A>>B>>K;

    long long a = 0;
    long long b = 0;
	if(K>A  || K>B){
		cout<<0;
		return 0;
	}

   
    if (A >= K) {
        long long wzdloz_B = B / K;
        long long wzdloz_A = max(0LL, (A / K) - 2);
        a = 2 * wzdloz_B + 2 * wzdloz_A;
    }

    if (B >= K) {
        long long wzdloz_A = A / K;
        long long wzdloz_B = max(0LL, (B / K) - 2);
        b = 2 * wzdloz_A + 2 * wzdloz_B;
    }

    long long o = max(a, b);
       	if(2*K>A  || 2*K>B){
		cout<<o/2;
		return 0;
	}

    cout <<o;

    return 0;
}